Looking for an insulation material? XPS is one of the available options. It is lightweight, easy to install and often chosen for areas where insulation is exposed to moisture or loads. However, it will not always be the only solution worth considering.
Expanded cork is an alternative. How does it differ from XPS, and when is it worth choosing? Let us take a closer look at the properties of both materials to make it easier to match the right insulation to a particular application.
Table of Contents 1. Introduction 2. XPS – the gold standard or an overrated classic? 3. Enter the alternative: a material from nature 4. Comparison with XPS 5. Summary 6. FAQ
XPS – when is it worth choosing?
XPS, or extruded polystyrene, is an insulation material valued for its low weight, good thermal insulation performance, compressive strength and low water absorption. It is used, among other things, to insulate foundations and roofs. It is easy to work with but, like any material, its properties need to be matched to the intended application.
It is also worth considering where it comes from and what happens to it at the end of its useful life. XPS is made from fossil-based raw materials. Used boards can be reused or recycled, although in practice this depends, among other things, on their condition and the recycling facilities available. That is why, when choosing insulation, it is worth comparing not only the technical performance but also the environmental impact of individual products.
Expanded cork – a natural alternative
Expanded cork is made from cork granules exposed to steam and high temperatures. During this process, the granules expand, while the natural components of cork, including suberin, bind them together to form boards. No synthetic adhesives need to be added when producing boards made solely from cork. style="font-size: 12pt;"> It is a plant-based material, harvested without cutting down cork oak trees – only the bark is removed, and it grows back over time.
Expanded cork boards can be used, among other things, to insulate walls, floors and roofs. When choosing them, however, it is important to consider the conditions they will be exposed to and the specifications of the particular product. Once removed, the boards may be reused or recycled, provided their condition and the way they were installed allow for it.
XPS vs expanded cork
XPS and expanded cork can both be used for thermal insulation, but they differ in their properties and applications. The thermal conductivity coefficient λ for expanded cork boards is usually around 0.037–0.040 W/(m·K), compared with approximately 0.032–0.036 W/(m·K) for XPS.
Expanded cork can also be useful in solutions designed to reduce noise, including impact sound. The final effect depends on the construction of the entire wall or floor, the thickness of the materials and the way they are installed.
Summary
XPS and expanded cork are insulation materials with different advantages. XPS stands out for its low water absorption and the availability of boards with high compressive strength, which makes it suitable for areas where insulation is exposed to moisture and loads. Expanded cork, on the other hand, is a plant-based material that can be used for thermal insulation as well as in solutions designed to reduce noise.
When choosing between them, it is worth comparing the specifications of individual products and the conditions in which they will be used. If environmental impact is also important, environmental product declarations can be helpful, as they take into account more than just the origin of the raw material. There is no single material that will be the best in every respect and for every application.
FAQ
1. What exactly is expanded cork? Expanded cork is a 100% natural insulation material. When exposed to steam and high temperatures, the granules bind together thanks to a naturally occurring substance called suberin. No chemical additives, adhesives or synthetic resins are required.
2. Why is cork more environmentally friendly than XPS? Cork is harvested from the bark of the cork oak without cutting down the tree. The bark grows back, and the next harvest usually takes place after at least nine years. XPS, by contrast, is made from fossil-based raw materials. That is an important difference.
3. How long does cork retain its properties? For several decades. It is resistant to ageing, does not absorb excessive amounts of water and does not deform easily. It is a material that can literally outlast the building itself.
4. Why are more and more architects and investors choosing cork? Because it is a material for the future – combining technical performance with environmental responsibility. It supports the idea of healthy building, improves acoustics, helps to stabilise the indoor environment and fits well with sustainable construction standards.
